title: Drug tolerance in replicating mycobacteria mediated by a macrophage-induced efflux mechanism.
abstract: Treatment of tuberculosis, a complex granulomatous disease, requires long-term multidrug therapy to overcome tolerance, an epigenetic drug resistance that is widely attributed to nonreplicating bacterial subpopulations. Here, we deploy Mycobacterium marinum-infected zebrafish larvae for in vivo characterization of antitubercular drug activity and tolerance. We describe the existence of multidrug-tolerant organisms that arise within days of infection, are enriched in the replicating intracellular population, and are amplified and disseminated by the tuberculous granuloma. Bacterial efflux pumps that are required for intracellular growth mediate this macrophage-induced tolerance. This tolerant population also develops when Mycobacterium tuberculosis infects cultured macrophages, suggesting that it contributes to the burden of drug tolerance in human tuberculosis. Efflux pump inhibitors like verapamil reduce this tolerance. Thus, the addition of this currently approved drug or more specific efflux pump inhibitors to standard antitubercular therapy should shorten the duration of curative treatment.
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Kristin N
authors.initials: KN
authors.lastname: Adams
authors.forename: Kevin
authors.initials: K
authors.lastname: Takaki
authors.forename: Lynn E
authors.initials: LE
authors.lastname: Connolly
authors.forename: Heather
authors.initials: H
authors.lastname: Wiedenhoft
authors.forename: Kathryn
authors.initials: K
authors.lastname: Winglee
authors.forename: Olivier
authors.initials: O
authors.lastname: Humbert
authors.forename: Paul H
authors.initials: PH
authors.lastname: Edelstein
authors.forename: Christine L
authors.initials: CL
authors.lastname: Cosma
authors.forename: Lalita
authors.initials: L
authors.lastname: Ramakrishnan
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D004195:Disease Models, Animal; D004361:Drug Tolerance; D006099:Granuloma / Q000503:physiopathology; D006801:Humans; D007814:Larva / Q000382:microbiology; D008264:Macrophages / Q000382:microbiology*; D049990:Membrane Transport Modulators / Q000494:pharmacology; D026901:Membrane Transport Proteins / Q000378:metabolism; D009165:Mycobacterium Infections, Nontuberculous / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D019910:Mycobacterium marinum / Q000187:drug effects / Q000502:physiology*; D009169:Mycobacterium tuberculosis / Q000502:physiology*; D014376:Tuberculosis / Q000188:drug therapy / Q000382:microbiology* / Q000473:pathology / Q000503:physiopathology; D014700:Verapamil / Q000494:pharmacology; D015027:Zebrafish / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D049990:Membrane Transport Modulators; D026901:Membrane Transport Proteins; D014700:Verapamil